开云体育

Homebrew sound-card isolator? matched to my uBitx today -- ran into unexpected problem:? ?begin transmission and instead of a solid TX, the push-to-talk chattered in and out of TX / RX / TX / RX about 5 times/second incessantly? ??

Sound card isolation system is a double transformer, gain pot, vox-type circuit with reed-relay output ( and Gerbers are on github) -- so quite puzzled why this happening when never happens with ICOMS..... and the SIGNALINK worked perfectly!

After multiple false theories I finally recognized that the PTT line goes DIRECTLY into a Nano.? ?Adding a bypass capacitor or two from PTT line to ground (all I had on hand were .047's would have preferred .01) -- and problem solved!!!!? ?Completely new discovery for me with this design.

The uBitx requires WAY more audio than I'm used to with mic input of ICOmS --had to change the fixed resistor in the audio attenuator to allow 10dB higher signal.? ? Then it could be adjusted with the gain potentiometer.? ??

After all THAT, I got it up on JS8 and immediately got 2 answers to my HB signal both giving me reasonable SNR's, and their signals were fine also.? ? Wandered down to FT8 land....wall to wall signals.? ?I'll fiddle more with that another day.? ??

Great rig.? ?Has taught me a TON -- thanks to you folks!

Gordon KX4Z

Gerbers for the sound isolator:???

开云体育

??Yes -- i've done the FT-817 bit for frequency control but always just did the signalink-type PTT.? ?I have not yet done any of the KD8CEC firmware.? ??

the easy digi should work FINE -- but it lacks the volume controls and I prefer a relay to the transistor for PTT.? ?My preferences, maybe not yours.? ?I bought one early on, but didn't think it would serve the needs of our group as well.? ?

PUT A CAPACIToR BETWEEN THE UBITX PTT LINE AND GrOuND -- like 0.01 uf.??

There are LOTS of ways to do digital, nothing says that my way is any better than others -- it is just what we've done for a few dozen systems locally.? ??

I havve been using the $4.75 Adafruit 1475 --- but there are probably much better choices out there for sound card...I just haven't studied it.? ? For the raspberry pi's that we have used these on, they need a "classless" sound dongle.

More power to you!

Gordon

开云体育